Unloading device.



J. TRIBE. UNLOADING DEVICE. APPLICATION rum) SEPT. a1, 1907.

Patented June 1, 1909.

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11N-LOADING DEVICE. APPLIUATION FILED SEPT. 21, 1907.

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J TBIBB UNLOADIN G DEVIOE. APPLICATION FILED SEPT. 21I 1907.

Patented June 1, '1909.

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BY Mmmm/Ex UNI srrs naar ermee.

JAMES TRIBE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERS COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF NEW JERSEY.

UNLOADING DEVICE Speccaton of Letters Patent.

Application led September 21, 1907.

Patented June 1, 1909.

Serial No. 393,960.

To all whom 'it may concern:

Be it known that I, JAMES TRIBE, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Unloading Device, of which the following is a specification.

This invention relates to unloading devices which are used in connection with air or gas compressors, blowing engines and the like, and more specifically it relates to that class of compressors in which an inlet valve to admit air to the compressing cylinder, which is adapted either to retain the air in said cylinder 0r allow it to escape therefrom freely into the atmosphere, is positivelyV actuated by some actuating mechanism oper ated in unison with the movements of the motor or engine which actuates the piston in the compressing cylinder. In this class of compressors means are provided to disconnect said valve from said operating mechanism when the air pressure in the delivery pipe or receiver attains a certain predetermined maximum, in order that said valve under such a condition of air pressure shall remain open, permitting air to freely enter the compressing cylinder and escape freely therefrom, whereby with an engine or motor which is designed to run at a substantially constant speed, the work performed by said engine or motor may be reduced to a minimum as long as the air pressure in the delivery pipe or receiver remains at the predetermined maximum.

Some of the compressors or blowing engines of the class above described are provided with a hook, catch or grab which is adapted to engage with the inlet valve to close said inlet valve, said hook being actuated from the engine or motor which actuates the piston in the compressing cylinder. This hook, valve and actuating mechanism may be and usually are of the same general construction as the valve operating mechanism used with Corliss engines, with this difference however, that an air actuated motor of some sort is used to keep the hook out 0f engagement with the valve so that the valve will not be operated instead of a speed governor being employed for this purpose, as is ordinarily the case with Corliss engines.

With compressors fitted With mechanism of the character above described, the hook will be actuated, usually oftener than once a second, ordinarily, say from 70 to 90 times per minute, and it is found in actual practice that when an air motor of ordinary construction is used to operate the cam against which the tail of the. hook strikes, the large number of blows per minute and their intensity cause a fluttering of the piston or movable element of the air motor, due probably to a local compression ofthe air adjacent thereto in said motor. This fluttering or movementvof the piston or movable element of said air motor is a serious source of annoyance when it is desired to control said inlet valve with only slight variation in air pressure, as, for eX- ample, within a minimum range of permissible variation of from half a pound to a pound difference of pressure.

This invention provides an apparatus by means of which the inlet valve or valves of a compressor of the type above described may be controlled with absolute certainty even by small variations in air pressure.

Referring to the drawings which accompany this specification and form a part thereof, and on which the same reference characters are used to designate the same elements on each of the several iigures,-Figure l illustrates a com ressing cylinder in elevation, the air contro ling motor being shown partly in section. Fig. 2 is an elevation of a part of the rear end of said compressor. Fig. 3 is an enlarged section of the air motor shown by Fig. 1, the motor illustrated being provided With .a single controlling connection. Fig. is an elevation, partly in section, of a modified construction of air controller. Fig. 5 is a fragmentary section of the compressing cylinder with the inlet valve shown in its closed position. Fig. 6 is a view similar to Fig. E?,

ut showing the inlet valve in its open position.

Referring to the drawings, the numeral 1 designates the cylinder of a double acting compressor or blowing engine provided with the piston rod 2, to which is connected thel piston of the compressor (not shown).

The numeral 3 designates the wrist plate, 4 the reach-rod, and the letter A the admission valve at one end generally, While the letter B designates the admission valve at the other end, and the letter C the air motor.

Each of the valves A, B, comprises a valve 5 and valve stem 6, a valve arm 7, and a bonnet 8. Supported upon the valve stem 6 is the movable cam 9 and the hook lever 10, l the piston rod 29 which passes freely through one end of which is connected with the wrist plate 3 by the connecting rod 11, while to the other end of said lever is pivoted the hook l2, provided with the usual spring 13, an d the tail piece 14.

In order that the valves may be properly adjusted to aline with the ports 15 and 16 in the cylinder, a stop 17 is provided against which a stop 13 is adapted to rest, stop 18 being carried by a lever 19, which is secured to the valve arm 7 by the adjustable rod or turnbuckle 20. As in this specific type of valve gear the valve bonnets and parts carried by the valve stem project some little distance from the side of the cylinder, a special construction is adopted for the stop members, the stop 17 being formed as a part of a bracket 21, which may be secured either to the base plate of the compressor, to the floor, or to any suitable foundation, the lever 19 being pivoted to this bracket.

The air motor C consists of a cylinder 22, closed at its lower end and open at its upper end, which cylinder is bolted to the floor or any convenient support, and Within this cylinder is inserted a second cylinder 23, which is also open at one end and which may, if desired, be closed at its other end, an aperture being provided for the passage of a piston rod therethrough. rhis second cylinder 23 is provided with an outwardly projecting flange 24, by which it can be secured to cylinder 22. However, any other suitable or preferred construction than that shown by the drawings may be adopted for connecting the two cylinders. The edge or lower end of cylinder 23 is ground or dressed to fit tightly against an annular ridge 220 which projects upwardly a short distance from the bottoni of cylinder 22, and an aperture 25 is provided, preferably being located in this ridge 220, through which communication is afforded between the interior of cylinder 23 and the annular space which exists between the two cylinders. The thoroughfare through said aperture is adapted te be regulated by some adjusting means, as, for example, the needle pointed screw 250.

The pipe 26 which leads from the compressed air pipe or reservoir (not shown) is provided with a valve 27, and communicates with the annular space between the two cylinders near the top thereof. Orifices 270 and 271, adapted to be closed by the plug 272, provide for introducing oil or other liquid into said cylinders, a cock 273 being provided through which air can escape from cylinder 22 when liquid is introduced thereinto.

Within the cylinder 23 is located the piston 28 provided with a series of grooves on its circumference to retain oil or liquid and pack the piston. Connected with the piston 2S is integrally with cylinder 23.

the aperture in the top of cylinder 23, no stuffing box being required on account of the packing grooves before mentioned, and this piston rod projects upwardly from said cylinder through a guide 30, formed preferabl Eneircling said piston rod and retained between said pil*- ton and the closed end of the cylinder 23, is h spiral spring 30() of the open or compression type, which is adapted to resist upward movement of the piston.

rThe piston rod is provided with a redueed upper portion whereby a shoulder is formed adapted to receive one or more weights 3]. Secured to the guide 3 by pivots, are bell crank levers, one arm of which is connected with a cam Q by the adjustable rod 32, the other arms 33 of which are retained between collars 34- and 35 upon the piston rod 2), whereby said bell crank levers are roeked by said piston rod in its movements.

The operation of the apparatus is as follows: The piston rod 2 being reciprocated. the wrist plate 3 is rocked, causing levers 1() to rock about the valve stems G and carry the hooks 12 up and down and with them the valve arm 7, whereby on the 11p-strokel of the hooks the valves are closed and remain closed during the compression stroke, as shown by Fig. 5, and on the down stroke of the. hooks the valves are opened and remain open during the suction stroke, as shown by Fig. G.

Should, now, the air pressure rise to the select ed amount, the oil or other liquid is forced from the annular space between the two cylinders through the restricted opening 25, the piston 2S is raised, the cams 9 are rotated about the valve stems G until they contact with the tail pieces 14, and, on further move,- ment, said tail pieces will release the hooks from the valve arms, thereby permitting thel hooks to rise without lifting the valve arms 7, the valves remaining open during what is normally the compression stroke, as well as during the suction stroke.

It will be seen that when the cams Q are engaged by the tail pieces 111-, severe blows will be struck depending both upon the number of movements per minute of the hooks and the steepness of the cam surfaces, and if it were not for the restricted aperture 25, the cams would be forced back, being only backedv up by the air cushion, but in actual practiee it is found that with the construction illustrated and described, in which the movement of the oil or other liquid through the restricted aperture 25 is retarded, the cams are held up to their work as though solidly fastened in place.

lt has been found in practice that when the aperture 25 is equivalent in cross section to about one per cent. of the piston area, with ordinary cylinder oil used as the liquid, thc

il (l operation of this apparatus is very satisfactory.

The apparatusl shown by Fig. 3 of the drawings 1s the same in all particulars as that shown by Fig. 1, with the exception that this air motor is provided with but a single bell crank lever and connecting rod to act upon a single cam or some other controlling device.

In practice, with a double acting compressing cylinder such as shown by Fig. l of the drawings, the cam 9 at one end of the cylinder is adjusted slightly in advance ofthe position occupied by the cam at the other end of the cylinder, so that one end of the cylinder is first unloaded and then the other, giving a very iine and accurate operation for the unloading device.

The apparatus disclosed by Fig. 4 of the drawings is in princi le of operation and construction substantia 1y the same as that disclosed by Fig. l, the only difference being that the cylinder 40 is provided for containing the piston 28, and a separate receptacle 41 is provided, for the liquid or oil, which communicates with the cylinder 40 through the pipe 42 (which is provided with a valve 44 for controlling the size of the thoroughfare through said pipe), the air pipe 26 being tapped into the cover of the receptacle 41.

What I claim is,- The combination of a cylinder, inlet and discharge conduits connected therewith, a valve in said inlet conduit, a stem for said valve, an arm on said stem, a hook engageable with said arm to close said valve, means for operating said hook, means for positioning said hook to eiect disengagement from sald arm, an adjustable weight for tending to locate said positioning means to allow vsaid hook to engage said arm, fluid pressure actuated means for tending to locate said positioning means to effect disengagement between jsaid hook and said arm, adjustable iuid friction means for retarding the movement of said positioning means, and a s ring oHering resistance to the movement o' said positioning means set up by said fluid pressure actuated means.

in testimony whereof, I aiiiX my signature in the presence of two witnesses.

JAMES TRIBE. Wvitnesses G. F. DE WEIN, FRANK E. DENNETT. 

